Ophthalmate detection in human plasma with LC-MS-MS

Area of Science:

• Biochemistry
• Clinical Chemistry
• Analytical Chemistry

Background:

• Ophthalmate (OPH) is a potential biomarker for hepatic glutathione homeostasis, but its accurate measurement in humans has been limited.
• Previous studies relied on animal models, hindering human OPH metabolism research.

Purpose of the Study:

• To investigate the impact of delayed sample preparation on ophthalmate (OPH) concentrations in human plasma.
• To develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for OPH measurement in human biological matrices.

Main Methods:

• Venous plasma samples from healthy volunteers were incubated at 4°C and 37°C to assess OPH stability over time.
• A validated LC-MS/MS method was applied to determine OPH concentrations in human plasma, arterial whole blood, and liver biopsies.
• Enzymatic degradation was evaluated by monitoring OPH levels after varying incubation periods.

Main Results:

• Significant OPH degradation (74.6%) was observed in plasma incubated at 37°C for 120 minutes, indicating enzymatic activity.
• The developed LC-MS/MS assay accurately quantified OPH in plasma, whole blood, and liver biopsies.
• Baseline OPH levels were determined in plasma (0.06±0.03 μmol/l), whole blood (16.1 μmol/l), and liver biopsies (80.0 μmol/kg).

Conclusions:

• Immediate sample deproteinization is essential to prevent enzymatic degradation and ensure reliable OPH measurements.
• The validated LC-MS/MS assay provides an accurate tool for quantifying OPH in human plasma, whole blood, and liver tissue.
• This assay facilitates further research into OPH as a biomarker for hepatic GSH homeostasis in humans.